Snap switch



0st, 14, 1952 o. B. SUTTON Erm.

SNAP SWITCH Filed Sept. 16, 1948 Patented Oct. 14, 1952 SNAPl SWITCHOtis B. Sutton, Canton, and Herbert W. Wilson, North Canton, Ohio,assignors to The Hoover Company, North Canton, Ohio, a corporation ofUhio 'Application September 16, 1948, Serial No. 49,562

4 Claims. (Cl. 20D-467) This invention relates to an improved snapswitch and more particularly to a simplified snap acting togglemechanism having fewer components of simplified design.

Accordingly, it is an object of the` present in' vention to provide asnap switch having a simplified toggle mechanism of fewer components,sturdier in construction, more positive in operation and of longer lifethan those heretofore known. Still other objects and advantages willbecome apparent from the following description taken in connection withthe accompanying drawings in which:

Figure l is a vertical sectional view through an illustrative embodimentof the invention;-

Figure 2 is a cross sectional view of the assembled switch on line 2 2of Figure l; and

Figure 3 is a perspective view oi a bearing plate employed in the`toggle assembly.

Casing halves i@ and ll are preferably formed from molded thermoplasticmaterial and meet along a vertical median plane to form a switchhousing. An irregularly shaped cavity i2 formed partially in each casinghalf houses the toggle mechanism, a part of the operating handle, andthe inner portion of the terminal members. An opening i3 extends fromthis cavity through the top of the casing halves and forms an operatingpassageway for the switch handle lf3.

The toggle mechanism unit will now be described. Two side links ofstamped insulation material lli-i6 have their upper ends journaled onpin l5 which, as shown, also pivotally supports operating handle Ill.Each link is provided with a keyholeslot il at the opposite end toreceive and support a contact bridging spindle i8 having rounded ends tofacilitate wiping action with the contacts. lThis spindle isconveniently turned from brass stock and is provided with end grooves toreceive the sideflinks and a substantially centrally disposed groove i9.Journaled in groove i9 is a T-shaped toggle strut 2i] which is stampedfrom sheet material. The top side oi the T is notched at 2l to form abearing with the bottom of groove i9 oi the spindle.

Projecting from the lower, pivoted end of handle M is a round endedtoggle pivot arm 22. This arm is shown integral with the handle and itis oiset from the vertical center line of the handle in each oi twoplanes at right angles to one another. The nature and extent of theoffset in each direction can be best understood by observation ofFigures 1 and 2. It will also be noted from Figure 2 that strut 20 isoffset intermediate its end so that its top inner 'face lits against oneface of pivot arm 22. The strut is held in the position just describedby a bearing platev 23 in cooperation with compression spring 24 thelower end of which rests against the inside T head of the strut. Theopposite end of the spring bears against the *lowerufsideio'l plate 23and holds it firmly Vagainst the rounded end of pivot'arm 22.

As best shown in'Figure v3,"washer' 2'3is dishd at its mid portion 25and is provided withfa guide slot 2t to receive the upper end of strut20; From the foregoing it will 'be cleanthat'the peculiar constructionof the washer of the bearing plate 23 togetherwith the slot 25'constitutes a very simple and yet positive means lost motion connectionfor locking the toggle"as'sernblytoi` gether while permitting limitedco-planarvmovee ment between the strut and theface of the pivot arm. Thespring presses against the T head of the strut to maintain the strut'iirmly seated in' groove I9 of the spindle while its upperendfmaintains the bearing plate firmly againstjtheround= ed edge oipivot arm 22. rhus, the spring Valways acts to urge the spindle and thepivot armiapart; The flat sides of the bearing plate cooperate with theupper end of the strut, the endoffthepivot arm and theinner faces oflinks i6 to 'maintain all of the parts in their properrelativepo's'ition at all times. v

The terminal anchor construction willzno'w'be described and willbeundrstood to besubstantially identical with that disclosed 'intheapplica-.f tion of Herbert W. Wilson (Hoover Case G-19) being ledconcurrently herewith. "It comprises kthree separate elements inaddition `tothe two casing halves. These are the two metal V,terminalstrips 2l, 28 and separatorstrip'ZB vorinsulationmaterial. `Theseelements fit about bosses 32 formed integrally with each of the cas-,-ing'halves anddescribed in detailr in the 'abovementioned application.The inner `ends of -.the

of bridging contact withthe terminal: strips.

The casing halves may be heldin assembled position by a pair .of rivets30, 3l the latterf'of which passes through terminals'2l, 28 and sepfarator 29, it being understood that the insulated bosses surroundvrivet, 3l vand separate it from each vof the terminals as well as fromthe 'sep-M arator strip. l f 1f-- In assembling the toggle mechanism,pinjllis passed through the opening'in handle I4 and side links i6, I6are tted over the` opposite endsuof the pin. Next, spindle i8 isassembled through keyholeopenings l1, Il in the lower endv of' the sidelinks. Next, spring 24 is insertedover strut 28 and bearing plate 23 isinserted over the upper .end of the strut. This assembly istheninserted3 betweenthc side links with notch 2| .of the T riding ingroove 'I9 ofthe spindle and the spring is compressed suii'ciently to permit bearingplate 23 to be inserted beneath the rounded end ef pivot arm 22.

The toggle unit is a stable assembly at this stage and may be readilyhandled without danger of the parts separating from one another. Next,place terminal strip 28 in Vposition over boss l32 in casing half I0,and insert the toggle unit in its proper position in cavity I2.Separator 29, top terminal 21 and casing half Il are added in the ordermentioned. Thereafter the assembly is securely locked together by theplacement of rivets. 30 and 3l; n I

As will be understood from the foregoing, the entire switch is readilyassembled without the use of any tools whatsoever it being merelynecessary toslip the parts together and place them vbetween the casinghalves. Furthermore it is noteworthy that no special jigs or otherxtures are required inthe assembly operation. v

The described construction permits of the use of a heavy compressionspring which is maintained against buckling by the single strut 20stamped from heavier material than is feasible to use. with priorconstructions making use of U- shaped toggle struts or their equivalent.It will further be clearvthat the use of a single strut permits the useof stronger and heavier parts in all components of the toggle unitwithout increasing the over-all dimensions thereof. This adds greatly tothe reliability, sturdiness, and posltiveness of action of the switch.It will be equally clear that the life of the parts will be materiallyincreased and that there Will be far less likelihood of damage theretoin the assembly operation.

, While only a single embodiment of the invention has been disclosed, itis to be understood that numerous lvariations in the design anddisposition of the parts is contemplated Awithout departing fromv thespint of the present invention.

It is to be understood' that the protection herein applied for is notconiined to the particular features or elements set outin the followingclaims. Protection is herein applied for for any one or more of thefeatures or elements referred to in the following claims or described inthe foregoing specification or shown in the accompanying drawings eitherindependently or in combination.

Y. 1. A toggle mechanism for a snap -action switch comprising agenerally U-shaped contact bridgingr means, means `for pivotallysupporting the upper ends.y of said U-shaped means for limitedoscillatory movement between closed-switch and openswitch positions, anoperating handle for said toggle mechanism, means providing a commonpivotal axis for said handle and for the upper ends of said U-shapedmeans, said handle including a pivot arm positioned between the legs ofsaid U-shaped means, a toggle strut comprising a single substantiallyflat, one piece, T-shaped member having a single leg and a single headof uniform thickness a centrally disposed notch in the top edge of saidT-head, a single centrally disposed annular groove in the bight portionof said U-shaped means having a width slightly greater than thethickness of said toggle strut for receiving and pivotally supportingthe notched .T head of said strut, the other end of said strut vbeingdisposed against one face of the pivot arm on said operating handle, abearing plate having a dished central portion adapted to bear againstthe end of said pivot arm and a single slot adjacent thereto adapted toreceive the end of said strut for free to and fro movement therethrough,and a compression spring supported between said bearing plate and the Thead on said strut, said spring acting to hold the aforementionedelements of vsaid toggle mechanism in assembled position aswell as meansfor resiliently holding said U-shaped contact bridging means in eithersaid closed-switch or said open-switch position.

2. A snap action switch comprising a two part housing of insulatingmaterial, a switch operating handle opening in said casing, a pivot pinextending crosswise of said opening and supported by said casing, anoperating handle mounted on said pivot pin and having a pivot armextending into said casing, a pair of links having one end pivoted tosaid pin at either side of said pivot arm, a contact bridging membercarried in the opposite ends of said links, a single one piece, T-shapedtoggle strut having a single leg and a single head stamped from sheetmaterial, a centrally disposed bearing notch on the top .of the T headof said strut, a single centrally disposed groove in. said contactbridging member having a width slightly greater than the thickness ofsaid strut in which said notched T head is pivotally seated, the end ofsaid strut opposite said T head being disposed adjacent one face of saidpivot arm, a bearing plate having a central depression to receive theend of said pivot arm and a slot through which the end of said strutslides freely, a compression spring closely embracing said strut anddisposed between said T head and said bearing plate so as to urge saidpivot arm away from said contact bridging member, and a pair of switchcontact members supported in said casing and disposed to be bridged bysaid contact bridging member when said snap acting mechanism is in oneoi its two stable positions.

3. A toggle mechanism as defined in claim l in which the center line ofsaid pivot arm is 01T set laterally from a median plane between andparallel to the legs of said U-shaped contact bridging member, saidtoggle strut being disposed on t'iat side of said pivot arm closer tosaid median plane whereby said strut and said compression springfunction smoothly and without transmitting a twisting movement to saidU- shaped member.

4. A toggle mechanism as defined in claim 1 in which the end of saidpivot arm in contact with said bearing plate is off set laterally from aplane which includes the entire pivotal axis of said operating handleand the longitudinal center line of said handle whereby said spring ismore eiective in holding said contact bridging means in closed-switchposition than in said open-switch position.

O'IIS B. SUTTON. HERBERT W. WILSON.

REFERENCES CITED The following references arefof record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,474,013 Benjamin Nov. 13, 19231,969,263 Gaynor Aug. '7, .1934

`1,998,962 Krieger Apr. 23, 1935 2,186,154 StOekIe Jan. 9, 1940 FOREIGNPATENTS Number Country Date 549,724 Great Britain Dec. 3, 1942

